Design of Production Systems: Types & Main Processes

Exam Presentation

Design of Production Systems:
Types and main Processes

Index
1. Introduction……………………………………………………………….8-10
2. Main Definitions………………………………………………………..12-13
3. Production Systems Classification………………………………15-29
1. 3-Axis classification
2. Philips classification
3. Wortmann classification
4. Designing Process of a Production System………….........31-60
1. Demand Analysis
2. Industrialization of the production process
3. Choice of the Architecture of the Production Systems
4. Dimensionig of production resoruces
5. Design of the system layout
5. Conclusion………………………………………………………………….62

Flexible Systeme 311.007 - Exam Presentation By Matteo Michele Damiani 1029296 2

Index
1. Introduction……………………………………………………………….8-10
1. Demand Analysis
5. Conclusion………………………………………………………………….62


1. Introduction (Red Line) (1/3)
 During the lectures we have talked about Flexible
Manufacturing Systems .

 Flexible Manufacturing System (FMS) are systems
with limited resources that can escape the problems
because they adapt to the evironment settings and
focus on the respect of the initial target.

 Now I am going to explain why i decided to present
this topic.

Introduction (Red Line) (2/3)
 We said how much is important to respect the basic
rules to make the system working without stops. This
principles were:
 Feed the machine to keep them running providing them
the best conditions;
 In case of problems it is important to lose the minimun
amount of time and bring them back to work.

 With my presentation, I do not focus only on the FMS,
I want to discuss which are the different kind of
production system.


Introduction (Red Line) (3/3)
 In the first part of this presentation I will describe definitions
and classifications that try to cover the totality of the production
systms.

 Then I will discuss how different systems respond to the
problems of the environment considering their final aim (E.g.
final aim of the FMS is to keeping the machine running).

 In every situation the first analysis is critical. It is essential to
define the target of the system to understand which is the best
configuration. My purpose is to report a framework which can be
used to set the perfetkt scenario which provide to the system the
best conditions.


Index
1. Introduction……………………………………………………………….8-10
1. Demand Analysis
5. Conclusion………………………………………………………………….62


2. Main Definitions (1/2)
 What is a Production Process?

 The Production Process is the TRANSFORMATION of
materials into products (economic goods), which takes
place in an industrial plant.

 The TRANSOFRMATION occurs thanks to energy
exchanges that imply changes in the physical and
chemical features of materials.


Main Definitions (2/2)
 What is a Production System?

 The Production System can be considered as the
production process together with all management
subsystems that lead to the achievement of the
transformations.


Index
1. Introduction……………………………………………………………….8-10
1. Demand Analysis
5. Conclusion………………………………………………………………….62


3. Production Systems Classification

 In this chapter i will discuss the classifications that
exist to categorize the kind of production and the
different type of lay-out of the manufacturing system.

 In the literature I found 3 relevant classification:
 3-Axes classification;
 Philips classification;
 Wortmann classification.


The 3-Axes classification (1/4)

It considers 3 different Axes that i will describe in detail in the next
slides.

The Demand Axis


3.1. The 3-Axes classification (2/4)

 The Demand Axis: it is based on the way in which the
request forms and then finds response from the market. It
identifies 3 cases:

 Production on individual orders (make to single order): the company
receives different orders for single products for which it is necessary
to develop the design and manufacturing cycle;

 Production on repetitive orders (make to repetitive order): the
company realizes a range of products with features defined by a
quite stable group of customers;

 Production on stock (make to stock): The company produces a quite
high volume of products before it receives the orders .


The Volume Axis


 The Volume Axis: it is based on the way the output is
realized. It also identifies 3 cases:

 Unite/project Production: it is “one of a kind production”, there is an
high variability of the production cycle. The production process is
organized to provide the maximun flexibility;

 Batch Production: batch of products are realized with an superior
amount respect to the real market request in order to keep a stock in
case in the future there will be the need to change the production
process;

 Continuous Production: technologic cycle keep costant for long time
period.


The Product Axis


 The Product Axis: it is based on the nature of the
production process that is realized. It identifies 2 cases:

 Process Production (bound technology cycle): in this kind of process
the elements that are part of the final product can not be easily
identified. The product can not be disassembled because the original
components are not recognizable anymore or they changed their
nature. E.g. production process to obtain: steel, paper, cement,
chemicals, pharmaceutical. The output of this kind of production is
often the raw material of another production process.

 Parts Production (unbound technologic cycle): the product is made
out of a components of different natures (e.g. cars, household
appliances, electronic equipment). The product can be assembled
and disassembled.


3.2. Philips classification (1/2)
 The aim of this classification is to determine the planning
and control criteria more suitable to the different
production situation.

 It considers 2 dimensions:

 The Production Volume: it corrisponds to the volume Axis of
the 3-Axes classification;

 The complicacy of the product: it corrisponds to the Product
Axis in of the 3-Axes models with the difference that is more
detailed.


Philips classification (2/2)
 The complicacy of the product increases gradually
moving from the products made of simple materials
from simple materials to more complex systems
consisting of a large number of parts.

 The concept of complicacy is related only to
the product and not to the specific process used. In
fact, not necessarily for a complex product the
technology of the single production process used is
complicated.


3.3. Wortmann classification (1/5)
 The Wortmann classification introduces the
dimension of the modality of the Production
Management. More precisely it considers the
Customer Order Decoupling point (CODP)

 Before the Customer Order Decoupling
(CODP) the production management is based on the
forecast. After the decoupling point, the production
management is based on the demand of the final
customer.


Wortmann classification (2/5)
 Based on the CODP, the Wortmann classification identifies
the following modalities for the production management:
 Make to Stock (MTS);
 Assemble to Order (ATO);
 Make to Order (MTO);
 Engineering to Order (ETO).

 This is how the original classification has been described.
There could added to that list also 2 other modalities that
are different facets of the basic ones.:
 Assemble To Stock (ATS): between
 Purchase To Order (PTO).


 Make to Stock (MTS): the customer's order addresses
the final stock of the finite products. In this category
we find the production based on the demand forecast.
Furthermore in this situation the product is simple.

 Assemble To Order (ATO): the customer’s order is
directed to the assembly plan of the finite product thus
the production of standard subgroups is made by
forecast. These standard subsystems are assembled
after the customer’s order according to his request
(customization).

 Make to Order (MTO): in this case the customer's
order addresses the initial planning phase of the
product’s components. The production can not start
before the customer’s order.

 Engineering To Order (ETO): the customer’s order is
addressed to the design phase of the product itself. It
is the typical case of the one of a kind products whose
production requires a large amount of time and
elevated costs (E.g. huge ships or planes).


Wortmann Classification (5/5)


Index
1. Introduction……………………………………………………………….8-10
1. Demand Analysis
5. Conclusion………………………………………………………………….62


4. Designing Process of a Production System (1/4)
 Most manufacturing companies do not have integrated
design. In these companies designers of the product do not
care about the machines needed to product their products.

 There are specialized people who consider the production
system and process, they are called technologist.

 The technologists who design the production system and
process often are consultants with relevant experiences in
that field, but they do not necessary belong to the
organization .


Designing Process of a Production System (2/4)
 On the other hand there are some large companies
that make integrated planning.

 For example in the automotive and aerospace sectors, many
companies have designers inside the firm with the task to design
the plant and as a consequence the production process.

 In this markets the production is often “made to order” so as we
have seen before this means that the customer requires a
particular product/service. Obviously the market of the
manufacturing machines does not offer production machines
standardized for every product. So in this case the production
would result integrated.


 Designing the production system means to design a complex set
of elements aimed at the creation of a product. The main goals
can be reassumed in two points:
 Choice of the manufacturing resources;
 Dimensioning of productive resources.

 These choices must be made about the following aspects:
 Plant;
 Machinery;
 Operators and necessary skills.

 In the next slides I will explain in detail the entire process and of
course the focus will be more on the machinery and on the plant
rather than on the operators and necessary skills.


 The phases of the Designing Process are the following:
1. Demand Analysis;
2. Industrialization of the production process (process
cycles);
3. Choice of the Architecture of the Production System
(both manufacturing and assembly);
4. Dimensioning of productive resources;
5. Design of the system layout:
 Dimensioning work stations;
 Dimensioning work spaces;


4.1. Demand Analysis
 Demand forecasting is the activity of estimating the
quantity of a product or service that consumers will
purchase. Demand forecasting involves techniques
including both qualitative and quantitative methods.

 In the design of the process of a production system
demand forecasting may be used in assessing future
capacity requirements.

 With the forecast of the capacity needed it is possible
to understand the amount of machinery.

4.2. Industrialization of the producion process
 This stage provides the work cycle that is a rational and orderly
succession of operations necessary to transform a raw product, or
one or more raw materials into a finished product.

 In this phase it is decided the kind of mechanical transformation
that will be needed for the realization of the product.


4.3 Choice of the Architecture of the Production Systems



Manufacturing

In the next slides i will describe
every single solution in detail.


Manufacturing - Job Shop (1/3)
 A Job Shop is a manufacturing system organized in
different work centers in which homogeneous
machines are placed.

 Labour is often the critical (limited) resource.

 Each product has its own routing (technological
cycle), that defines a route through several types of
machines. There are several alternative cycles
(routings).

Advantages of the Job Shop:

 Flows are extremely interwoven for this reason it
has a very high flexibility.

 Availability of general-purpose machines and thus
ability to produce a potentially infinite mix of
items.

 Possibility to set alternative cycles (routings)

Disadvantages of the Job Shop:

 Products pass most of the time waiting or queuing.
 Difficult to control product flow.
 High number of work in progress.
 Low machine saturation.
 Quality level not much constant.
 Difficult to forecast production and to foresee
bottlenecks.
 High dependence on performance by the mix of
product to be manufactured.

Manufacturing - Cells (1/3)
 Machines are arranged according to product
homogeneity. The group of similar product are called
families.

 Cells are designed using groups made of different kind
of machines.

 There are no flows among cells.


Advantages of the manufacturing cells:

 Shorter Lead time.
 Lower Work In Progress.
 Customer-oriented.
 Multitask Labour.
 Setup Reduction.
 Better utilization of shop floor space.
 Higher saturation.

Disadvantages of the manufacturing cells:

 Balancing loss of workloads among cells.
 Difficult to gain completely autonomous cells.
 High implementation costs (due to layout review).
 Difficult to manage mix turbulence.


Manufacturing - Transfer Lines
 Stages (stations) are arranged in a sequential line, not necessarily
a straight line. The sequence respects the order of the
technological cycle of the product manufacturing.

 Machines are dedicated to the production of a single product or a
product family.

 Production rates are extremely high.

 The solution is efficent but rigid.

 It is easy to manage this system but the flexibility is very low.


Manufacturing - Synthesis


4.3 Choice of the Architecture of the Production Systems

Assembly


Assembly – Fixed Position
 Suitable for assemblies of big and heavy objects (tool-
machines, aircrafts...).

 The object that has to be assembled keeps a fixed position,
while components, tools and labour converge on the
assembly-site.

Assembly – Shop
 It is a system configuration in which a limited
set of stations has a significant portion of the assembly
cycle of a family of products.


Assembly – Transfer lines (1/2)
 The assembly operations are distributed across
multiple workstations and the product to be
assembled is transferred between the stations through
a manual or automatic system. Regarding the
conditions of movement the following solutions are
possible:
 Fixed transfer line;
 Continuous transfer line;
 Not constrained transfer line.


Assembly – Fixed Transfer System
 Classical solution of the assembly line belt with a
number of stations where one or more workers can
work according to the size of the object.

 The stations are linked by a transportation system that
after a certain time (pace) transfers a sub-assembled
part from a station to the following on.


Assembly – Continuous Transfer System
 The line consists of a series of stations placed
along a conveyor in continuous motion that range the
products at a constant distance. The speed is
slow but steady. The time take to traverse the station is
used for assembly operations.

Assembly – Not constrained Transfer System
 All the workstations are arranged in sequence with
buffers between them.


Assembly – Transfer lines (2/2)
 Advantages:
 compared to fixed-position assembly, they allow high
volume production with lower costs and space
utilization;
 the solution of transfer line maximizes efficiency and
plant rationality;

 Disadvantages
 The cycle time is fixed but not the length of manual
operations;
 job sharing out
 High time-to-start of new productions


Assembly - Synthesis


Overview Picture


4.4. Dimensioning of Productive Resources
1. Identification of the product mix used as a reference.
2. Development of the processing cycles of the parts.
3. Identification of the machines needed.
4. Sum of workload by type piece / machine.
5. Calculation requirements productive
hours (per unit).
6. Calculation of hours available (per unit).
7. Calculation of the number of machines (per shift).
8. Calculation of the number of rounds cheaper.


4.5. Design of the system layout – work stations (1/3)
 The purpose of this phase is to:
 Simplify manufacturing process:
 Arrange the plants to ensure the maximum degree of using
them;
 Do not create congestion material;
 Build a good balance of production lines;
 Ensure flexibility '(for change of mix);
 Ensure elasticity '(for volume changes);
 Reduce the cost of transporting materials;
 Minimize inventory production;
 Use the available space as efficiently as;


Design of the system layout – work stations (2/3)
 Different types of layout:
 Layout for the process: equipment functionally identical are grouped in the
same department;
 Layout by product: machines are arranged in the order provided for in
the production cycle technology;
 Layout mixed (family fixed point, etc.).

 Phases of the design lay-out:
 Analysis of material flow;
 Study of service;
 Determination of flow chart and / or relationship between the activities;
 Determining the space required determination of the spacer equired;
 Determination of the diagram of the relationships betweens paces;
 Draw up an initial layout;
 Reorganisation of the diagram of the relationship between space
and the first lay-out;


Design of the system layout – work stations (3/3)


Design of the system layout – works spaces (1/2)
 It is necessary to analyze the operational task to
identify the possible elements of stress and
operational risk, to define requirements and design
guidelines.

 Analysis of factors: posture and movements,
information and control, environmental factors,
organization.


Design of the system layout – works spaces (2/2)


Index
1. Introduction……………………………………………………………….8-10
1. Demand Analysis
5. Conclusion………………………………………………………………….62


5. Conclusion (Red Line)
 In this presentation I firstly descibed the definition and classification
with the purposo to sjow how differentiated is the world of the
production systems.

 Afterwards in the second part i focused the attention on the designing
phase and the conclusion that we can draw is the following:
 The choices of the designing phase of a production system are taken
differently depending on the final goal.
 Sometimes it is better to have the maximum flexibility, sometimes it is
better to have a constant system because the productiviy is the main
purpose.
 There is not the perfect configuration that fits every situation; It is
essential to find the best adapted configuration that is an arrangement
of parts or elements. The outcome of the production system depends
on the configuration.


References
 Garetti, M. & Taish M. (1995): “Sistemi di Produzione
Automatizzati”, CUSL (Milano), ISBN: 888132010X.
 Sinesi A. (2008): “Introduction to Logistic & Production
System”, Politecnico di Milano, Italy.
 Siensi A. (2008): “Introduction to Production System”,
Politecnico di Milano, Italy.
 Terzi S. (2010): “Progettazione dei Sistemi Produttivi”,
Politecnico di Milano, Italy.
 www.wikipedia.it
 www.google.com ( images)
 Flexible Manufacturing Systems notes.


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